In the shipping industry, the use of large cargo containers in which cargo to be shipped from one location to another is loaded. The containers are such that they can be easily and conveniently moved from one transport vehicle or vessel to another for transport across land and/or sea. The provision and use of such containers has been adopted to eliminate the necessity of manually tranferring cargo from vessel to vessel and from vehicle to vehicle in its course of being transported from one place to another and was once common practice.
The cargo containers in use today have become substantially dimensionally and structurally standardized and are such that they can be easily, conveniently and securely arranged in vertical stacked side by side and end to end relationship with each other whereby the most effective and economical use of hold and deck space on ships and the like, on which such containers are placed, is assured.
The principal shortcoming found in the use of cargo containers of the character referred to above resides in the fact that in normal use of such containers, it is not infrequent that they must be transported empty from a station or site of delivery of cargo to a next site or station for receipt or loading of cargo. Such transporting of empty containers is non-profitable since each such container occupies valuable and costly space which could otherwise accommodate a loaded or filled container. Further, the handling and shipping of both filled or loaded and empty containers creates a multitude of other problems. One such problem resides in arranging light, empty containers and heavy, loaded containers aborad ships in such a manner that the ships are properly and safely trimmed.
It is not infrequent that the majority of containers transported by a transoceanic cargo container ship are empty containers. In such instances, the voyage of such ships is uneconomical and would result in substantial financial losses if it were not for the fact that such losses are covered by increased charges exacted for the handling of and transporting of filled containers.
It has long been recognized that great economic savings in shipping by containers could be realized if empty containers could be folded or collapsed so that they occupy a small fraction of the space they occupy when in their normal configuration and so that less space need be sacrificed in the transporting of empty containers.
If two containers, when collapsed, could occupy the space of one container in its normal configuration, the cost of shipping those empty collapsed containers would be reduced about one-half. If. for example, the space occupied by such collapsible containers was one-sixth the space they nornally occupy, six empty containers would occupy the space of one full container and the cost of shipping each empty collapsed container would be about one-sixth cost of shipping an empty non-collapsible container.
The prior art has proposed a number of collapsible inter-engageable or nesting cargo container structures intended to effectively reduce the space required for their shipment when they are empty. While certain proposed collapsible containers might well serve such an end, it is understood that they are seriously wanting in certain material respects.
The first most common and serious shortcoming in most of the collapsible cargo containers that have been proposed by the prior art resides in the fact that special structural features are incorporated in them which renders them incompatible for use in combination or in conjunction with existing, standard, cargo containers. Accordingly, if such containers were to be adopted, an entirely new supply of containers and new container handling equipment would have to be provided. The costs involved in such an adoption of new containers and related equipment would be prohibitive.
Another common shortcoming found in collapsible cargo containers proposed by the prior art is the inclusion of removable or separable parts which are subject to being misplaced, lost, damaged and/or stolen. Experience has taught that if parts of equipment such as cargo containers can be removed and lost or readily damaged, such parts will be removed, lost and/or damaged in the normal course of their use and that great difficulties and inconveniences will be experienced in maintaining such containers.
Yet another shortcoming found in collapsible containers proposed by the prior art is the lack of structural features which enable or facilitate the folding down and setting up or opening of such containers in a simple and effective manner, with commonly used and available tools and equipment.